The material SRS-A (slow reacting substance of anaphylaxis) like histamine is released from the cells of mammals during an allergic reaction. The SRS-A excreted by the cells contracts smooth muscle tissue producing such allergic responses as asthmatic attacks. Thus, there has been a great need for pharmaceuticals which inhibit the synthesis of SRS-A to prevent its release by the cells during an allergic response.
Conventional anti-allergic drugs such as antihistamines, while effective in neutralizing the histamine produced during an allergic response, have been ineffective in neutralizing or antagonizing the effects of SRS-A. This has limited the usefulness of these antihistamines as anti-asthmatic agents. Therefore, it has long been desired to develop compounds which will specifically inhibit the synthesis of SRS-A by the cells of a mammal to prevent its release during an allergic response and prevent the conditions associated with such an allergic response.